GLOSSARY. 785 



Hastate. Halberd-shaped. Applied to leaves that are of a general tri- 

 angular shape, but have at the base two lateral lobes which diverge 



at right angles from the principal axis, as in sheep sorrel (p. 524). 

 Haustoria. The roots of parasitic plants which penetrate the tissues of 



their hosts (p. 306). 

 Head. Applied to the inflorescence of the Compositae which consists of 



clusters of nearly sessile flowers. 

 Heterosporous. Plants which produce two kinds of asexual spores (p. 



86). 

 Hilum. The scar resulting when the ripe seed becomes detached from 



its stalk (p. 425). Also erroneously applied to the starch grain in 



describing the nucleus or point of origin of growth (p. 144). It was 



at one time supposed that the starch grain was attached to the cell 



at this point. 

 Hirsute. Bristly hairy. 

 Hyaline. Thin, transparent or translucent. 

 Hydrophilous. Plants which are pollinated by the aid of water currents 



(p. 401). 



Hymenium. The spore-bearing surface of fungi as in mushrooms (p. 57). 

 Hypha. The filament or thread-like cell such as is formed by most fungi 



(p. 41). The mass or mat of interwoven hyphae constitutes the 



mycelium. 

 Hypocotyl (Radicle). The axis of the embryo below the cotyledon (p. 



426). 

 Hypogynous. A flower in which the petals and stamens are situated on 



the receptacle beneath the ovary and free from it and the calyx (pp. 



120 and 389). The ovary of such a flower is said to be superior. 

 Imbricate. A type of prefloration in which the sepals and petals interlap 



each other (p. 389). 

 Imperfect. Applied to flowers in which the fertile elements consist of 



pistils or stamens only (p. 392). 

 Incised. Applied to leaves having the margin cut into sharp lobes, as 



in the scarlet oak. 

 Included. Applied to stamens' which do not project beyond the tube of 



the corolla. 

 Incumbent. Cotyledons which are so folded that the dorsal surface of 



one is opposite to the hypocotyl, e.g. the seeds of mustard and many 



other Cruciferae. 

 Indefinite. Usually applied to the parts of flowers, as of stamens, when 



there are more than ten, and not clearly in multiples of the ground 



plan of the flower. 

 Indehiscent. Applied to fruits wliich do not open along the sutures to 



allow the discharge of seeds. Also applied to the anther. 

 Indusium. The shield-like covering of the sori in ferns (p. 89). 

 Inferior. Applied to an ovary that is adnate to the calyx. 

 Inflorescence. * The flower or flower cluster. The study of the arrange- 

 ment of flowers on the axis is known as anthotaxy (p. 393). 

 Infundibuliform. Funnel-shaped, as the corolla of the morning glory 



(p. 669). 

 Innate. Borne on the summit of the axis. Applied to the usual type 



of anther (p. 381). 



Internode. That portion of the axis between two nodes (p. 320). 

 Introrse. Anthers which are so attached to the filament that they face 



the axis of the flower (p. 379). 

 Involucre. A spiral or circle of bracts subtending a single flower or a 



flower head (p. 395). 



